CVE-2022-27255 in eCos RSDK
Summary
by MITRE • 08/01/2022
In Realtek eCos RSDK 1.5.7p1 and MSDK 4.9.4p1, the SIP ALG function that rewrites SDP data has a stack-based buffer overflow. This allows an attacker to remotely execute code without authentication via a crafted SIP packet that contains malicious SDP data.
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Analysis
by VulDB Data Team • 08/29/2022
The vulnerability identified as CVE-2022-27255 affects Realtek eCos RSDK 1.5.7p1 and MSDK 4.9.4p1 implementations where the Session Initiation Protocol Application Layer Gateway (SIP ALG) function processes Session Description Protocol (SDP) data. This flaw resides within the network infrastructure components that handle voice and video communication sessions, specifically targeting the processing of SDP information which describes session parameters and media capabilities. The vulnerability manifests as a stack-based buffer overflow, a critical class of memory corruption flaw that can lead to arbitrary code execution when exploited.
The technical implementation of this vulnerability occurs within the SIP ALG functionality that rewrites SDP data to ensure proper network traversal and NAT traversal for VoIP communications. When a maliciously crafted SIP packet containing specially formatted SDP data is received, the application fails to properly validate the length of incoming data before copying it into a fixed-size stack buffer. This lack of proper bounds checking creates a condition where an attacker can overflow the buffer and overwrite adjacent memory locations including return addresses and control data. The vulnerability is particularly dangerous because it requires no authentication to exploit, making it accessible to remote attackers who can craft malicious packets from outside the network perimeter.
The operational impact of this vulnerability extends beyond simple code execution as it represents a severe threat to network infrastructure security. Attackers can leverage this flaw to gain unauthorized control of devices running the affected Realtek software, potentially leading to complete system compromise, data exfiltration, or use of the compromised device as a pivot point for further attacks within the network. The vulnerability affects network equipment such as routers, firewalls, and VoIP gateways that implement Realtek's embedded software stacks, potentially impacting enterprise communication systems, service provider networks, and home gateway devices. This weakness aligns with CWE-121, stack-based buffer overflow, and maps to ATT&CK technique T1203, Exploitation for Client Execution, as it enables remote code execution through network-based attacks.
Mitigation strategies for CVE-2022-27255 should prioritize immediate firmware updates from Realtek and affected vendors who may have implemented patches for this vulnerability. Network administrators should implement ingress filtering and monitoring to detect anomalous SIP traffic patterns that might indicate exploitation attempts. The implementation of network segmentation and access control lists can help limit the potential impact if exploitation occurs, while regular security assessments of network infrastructure components can identify other vulnerable systems running the affected software versions. Organizations should also consider deploying intrusion detection systems with signature-based detection capabilities specifically designed to identify crafted SIP packets that attempt to exploit this buffer overflow vulnerability, ensuring comprehensive protection against this remote code execution threat.